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Wacky calibration issues

Posted: Mon May 20, 2013 3:08 am
by noddynomolos
Dear Group,
I have had a few issues with getting my Max up and printing. I am running repatier host with Repatier max firmware. I have sliced a unique 200mm bed leveling print and put some pictures on flicker http://www.flickr.com/photos/94291182@N02/8756818808/ (not sure how to upload the pictures to the forum from flicker). In the image you can see the huge variation in print thickness at different places on the onyx hotbed. I have Calibrated the towers using both paper method as well as a dial indecator (to within a thousandth), adjusted the Delta Radius, and calibrated the extruder (retraction is set to 2mm because of strings and blobs). See this in http://www.flickr.com/photos/94291182@N02/8756812408/
THe photos where taken looking between the x and Y towers looking toward the z tower. you can see the layer thickness issue between the z and x tower in this picture http://www.flickr.com/photos/94291182@N02/8756798908/
What is curious about the calibration is when I dial in the Z,X, Y towers and center z all is well. However, if I manually jog the hotend toward the x tower the hotend pushes harder and harder into the paper overlying the glass. If I move toward the y tower the reverse. Remember that all towers measured equal before. It all goes out of wack when I either manually jog or run a print. Could the values in the firmware be off? Perhaps some of the arm length or effector length be off?
Here is a picture of a rod end that just finished printing http://www.flickr.com/photos/94291182@N02/8756089183/ It is supposed to be circular not elliptical :) here is a slightly different angle http://www.flickr.com/photos/94291182@N02/8757213876/
Any ideas guys.
Yours,
Don S
ps I had a close look at all the end stop switches and all are clear and are functioning correctly. Belts and pulleys are clear as well..

Re: Wacky calibration issues

Posted: Mon May 20, 2013 4:31 am
by cambo3d
1. have you made sure your print bed/ print surface is level? before you do start calibrating.
2. do you calibrate at operating temperature?
3. lock tight your top hot end nut. this has a tendency to come undone under heating and cooling cycles.
4. have you checked the alignment of your laser cut parts, and checked towers are square and perpendicular to the build surface?
5. make sure your end stops make good contact with the screw head. some slight variation may cause your axis to be slightly off.
6. rod end, could just be the filament not sticking to the surface well enough causing it to drag. What are you using to help the plastic adhere to the print surface.

Re: Wacky calibration issues

Posted: Mon May 20, 2013 12:02 pm
by noddynomolos
Hi Cambo3d,
Thanks for your ideas.
I am using hairspray and getting good adhesion.
Yes all calibration is done at working temp. 220 hotend 85 hotbed
I suspect you might be onto something with the tower alignment me x tower could be a bit off. There where a few units shipped with laser cut parts that where not true.
The bed appears to be level. But that needs further investigation.
Did you have to shim your hotbed?
I just checked mine with a level and a metal straight edge. It is almost the opposite to what I am seeing while printing. The bed is higher on the y tower side. During printing or appears that the bed is higher on the x tower side.. Leads me to think its not a mechanical issue but a firmware issue. A value I have changed by mistake or something.
Thanks for your ideas...

Re: Wacky calibration issues

Posted: Mon May 20, 2013 12:43 pm
by cambo3d
couple more things to check.

are your pulley set screws tight, I recommend grinding in a flat on the stepper shaft to combat pulley slipping.

my build surface isn't shimmed, but I made sure my rostock frame was completely flat/ level and sqaured. that seemed to solve my initial issues of the non level build surface.

Re: Wacky calibration issues

Posted: Mon May 20, 2013 3:48 pm
by noddynomolos
Dear Cambo3d et al,
I read you build thread earlier and saw that you has flattened your step motor shaft. I immediatly did the same. I found that one of the set screws had stripped its threads so I have used some teflon tape to tighten up the sloppyness. I am contemplating ordering new pulley and belts sets as I am still using the old pulleys. Yes I think I have an issue with the original build. I found that my x tower seems to be eve rso slightly tilted toward the space between the y tower. Not sure if it is coming from the top or the actual tower mount. I just tried adjusting the tension on the bolts but had little effect..
Will keep you posted... Cheers
Don

Re: Wacky calibration issues

Posted: Mon May 20, 2013 4:19 pm
by foshon
Did I read that right , that circle was printed at 200mm/s?

Re: Wacky calibration issues

Posted: Mon May 20, 2013 4:47 pm
by noddynomolos
No, 30mm and its a 200mm circle